载畜率对短花针茅荒漠草原土壤物理特性的影响(英文)

Effect of Stocking Rate on Soil Physical Properties in a Stipa breviflora Desert Steppe

放牧对土壤物理特性的影响至关重要.为了研究放牧对土壤物理特性的影响,在内蒙古荒漠草原上开展了不同绵羊载畜率放牧试验.试验采取完全随机区组设计,设置4个不同载畜率处理,3次重复.4个处理分别是对照(CK)、轻度放牧(LG)、中度放牧(MG)和重度放牧(HG),相应的载畜率分别是0,0.15,0.30和0.45只羊/(公顷.月).放牧时间为每年6月-11月.从2004年到2006年的放牧期间,每月测定一次土壤含水量和土壤容重,土壤紧实度和机械组成每年秋季测定一次.通过对测定数据的分析表明,土壤表层(0-10cm)的含水量从对照到轻度放牧显著(p<0.05)增加,然后随着载畜率的增大明显(p<0.05)降低.土壤容重在不同载畜率条件下没有明显变化(p>0.05),但土壤紧实度随载畜率的增加显著(p<0.05)增大.中度和重度放牧显著降低了土壤黏粒的含量(p<0.05).重度放牧加快了草地土壤水分的损失,进而增加了土壤的紧实度,使草地土壤发生退化.载畜率和土壤水分是影响荒漠草原可持续管理的关键因子,轻度载畜率是实现草地的可持续发展的最适宜载畜率.

Grazing has a critical effect on the soil physical properties in the desert steppe.An experiment was conducted to investigate how soil physical properties were affected by sheep stocking rate in a desert steppe of Inner Mongolia P.R.China.A randomized complete block design was used with 3 replications × four grazing treatments:non-grazed exclosure(Control),lightly grazed(LG),moderately grazed(MG) and heavily grazed(HG).The stocking rates were 0,0.15,0.30 and 0.45 sheep per hm2 per month,for the Control,LG,MG and HG,respectively.Sheep were grazed from June to November.Soil water and bulk density were measured monthly during the grazing period from June to November,during 2004 to 2006.Soil compaction and particle size analysis were conducted once in autumn each year.The results showed that soil surface(0-10 cm)water content increased(p < 0.05) from the control to LG,and then decreased(p < 0.05) with increasing the stocking rate.Soil bulk density(0-5 cm) was unaffected by stocking rate but soil compaction increased(p < 0.05) with increasing stocking rate.Moderate and heavy stocking rates decreased(p < 0.05) the clay percentage.Heavy stocking rate accelerated the loss of soil water,which further increased soil compaction and degrading grassland soil condition.Stocking rate and soil water are the most critical factors for the sustainable management of desert steppe.Light grazing recommended on management practice in this region for the sustainable development.